The heart is a hollow muscular organ of a somewhat conical form; it lies between the lungs in the middle mediastinum and is enclosed in the pericardium. The heart generally rests obliquely in the chest behind the body of the sternum and adjoining parts of the rib cartilages, and typically projects farther into the left than into the right half of the thoracic cavity so that about one-third is situated on the right and two-thirds on the left of the median plane. The heart is subdivided by septa into right and left halves, and a constriction subdivides each half of the organ into two cavities, the upper cavity being called the atrium, the lower the ventricle. The heart therefore consists of four chambers; the right and left atria, and right and left ventricles, with one-way flow valves between respective atria and ventricles and at the outlet from the ventricles.
Heart valve repair and/or replacement may be indicated when there is a narrowing of a native heart valve, commonly referred to as stenosis, or when the native valve leaks or regurgitates, such as when the leaflets are calcified. Repairing a valve may include reshaping the valve annulus using, e.g., an annuloplasty ring, and/or repairing/replacing chordae tendinae, and/or repairing valve leaflets. When replacing the valve, the native valve may be excised and replaced with either a biologic or a mechanical valve.
Conventional heart valve surgery is an open-heart procedure conducted under general anesthesia, and is a highly invasive operation. The first 2-3 days following surgery are usually spent in an intensive care unit where heart functions can be closely monitored. The average hospital stay is between 1 to 2 weeks, with several more weeks to months required for complete recovery.
In recent years, advancements in minimally-invasive surgery and interventional cardiology have encouraged some investigators to pursue percutaneous repair and/or replacement of heart valves. Percutaneous Valve Technologies (“PVT”), formerly of Fort Lee, N.J. and now part of Edwards Lifesciences of Irvine, Calif., has developed a plastically- or balloon-expandable stent integrated with a bioprosthetic valve. The stent/valve device, now called the Edwards Sapien™ Heart Valve, is deployed across the native diseased valve to permanently hold the valve open, thereby alleviating a need to excise the native valve. The Edwards Sapien™ Heart Valve is designed for delivery with the RetroFlex™ delivery system in a cardiac catheterization laboratory under local anesthesia using fluoroscopic guidance, thereby avoiding general anesthesia and open-heart surgery.
Some researchers propose implanting prosthetic heart valves at the valve annulus using a direct-access transapical approach. See, e.g., U.S. Patent Publication No. 2006-0074484. For replacing an aortic valve, access can be gained via the left ventricular apex (LVA), which is directed downward, forward, and to the left in the patient's chest (from the perspective of the patient). The apex typically lies behind the fifth left intercostal space (or between the fourth and fifth), 8 to 9 cm from the mid-sternal line, and about 4 cm below and 2 mm to the medial side of the left mammary papilla. Access to the left ventricle may therefore be attained through an intercostal incision positioned over the fifth left intercostal space. Such an approach is often termed a “mini-thoracotomy,” and lends itself to surgical operations on the heart carried out using one or more short tubes or “ports”—thus, the operations are often referred to as “port-access” procedures.
Dehdashtian in U.S. Patent Publication No. 2007-0112422 discloses a port-access delivery system for transapical delivery of a prosthetic heart valve including a balloon catheter having a steering mechanism thereon that passes through an access device such as an introducer. The surgeon forms a puncture in the apex with a needle, advances a guidewire, then a dilator, and finally the introducer. Purse string sutures are pre-installed around the puncture to seal against blood leakage around the various devices and provide a closure after the procedure. During the procedure the doctor/assistant is able to apply tension to the purse-string-suture, which prevents inadvertent blood loss. After the deployment of the heart valve, the purse sting-suture is then used to permanently close the opening of the heart by drawing concentric tension on the suture ends, and tying a secure knot. The aforementioned Edwards Sapien™ Heart Valve may be inserted transapically with the Ascendra™ delivery system, much like the system disclosed in Dehdashtian.
Often, direct- or port-access techniques are conducted or proposed for off-pump, aka “beating heart” procedures, in which the heart remains beating as opposed to the patient being placed on a cardiopulmonary bypass system. Challenges remain in stabilizing various instruments used during these procedures, as well as in stabilizing targeted patient tissues and/or organs. For example, a number of devices are available that directly contact the heart muscle for stabilizing an area around a cardiac artery for coronary artery bypass graft (CABG) procedures. These systems typically include a soft contact member having suction that brackets a coronary artery, or grabs and manipulates an area of the heart for better access. These systems are mostly concerned with holding still a discrete surface area of the heart for direct operation thereon, and are not designed for operations carried out by instruments that extend within the beating heart, i.e., for intracardiac procedures.
What has been needed is a system and method for stabilizing the heart and the operating instruments, providing access to the heart interior, and sealing tissue punctures at the conclusion of the procedure. The current invention meets these needs.